The aim of the traditional anti-acid is to coat the sensitive tissues and neutralize acid within the stomach. Attempts have been made to protect the sensitive esophageal tissues from the effect of stomach acids which is sometimes allowed to reflux up and out of the stomach, into the esophagus. The acid damages this sensitive tissue, causing scarring and constriction which can lead to difficulty in swallowing. The common time during which this reflux occurs is in bed, when the patient is lying down, and the effect of gravity aids the acid in its exit from the stomach.
Traditional anti-acid liquids simply drain down into the stomach, leaving the esophagus unprotected. Other forms of medication attempt to inhibit the creation of acid by administration of biochemical modulators. This is only partially effective and the medication is expensive and not free of side effects. There is another form of anti-acid which in theory is designed to bubble up, and is referred to as a "foam tab". This design is ineffective at protecting the esophagus, and is no better than the liquid or pill form of chewable anti-acids, in that it is confined to the stomach, and its effects and benefits are limited to the stomach.